Ski with Swingable Tail

ABSTRACT

Disclosed is a ski having a front ski section and a rear ski section, each having a central longitudinal axis and a skiing surface. Boot binding fixing locations are provided on the front ski section. The rear ski section is connected to the front ski section rearward of the boot binding fixing locations such that, in a neutral configuration, the central longitudinal axes of the ski sections are substantially in linear alignment, and the skiing surfaces of the ski sections are substantially in planar alignment. The rear ski section is capable of swinging sideways relative to the front ski section whereby the central longitudinal axes of the ski sections move out of linear alignment. The rear ski section is capable of moving up and down relative to the front ski section whereby the skiing surfaces of the ski sections move out of planar alignment.

The present invention relates to a new type of ski, and to a pair of such skis.

Turning is a particularly important aspect of skiing. Modern skis are typically formed with at least some degree of side cut, such that the ski is broader at the head and sometimes the tail of the ski than at the mid-section. The resulting parabolic or curved side edges of the ski make turning simpler and less strenuous than with straight sided skis, as the skier merely has to roll the skis on to their edges to carve a natural arc through the snow. In general, the deeper the side cut, the tighter the turn radius of the ski, and the less work the skier has to do to effect a turn.

Nevertheless, co-ordinating the necessary actions to execute a turn correctly remains a difficult skill to learn.

Many skiers find that turning is easier and less strenuous using short skis known as snow blades, which are typically half the length of an average adult ski. The reduced surface area in contact with the ground means that the frictional forces which resist turning are reduced, making turning significantly easier. However, the reduced surface area also makes snow blades significantly less stable than longer, conventional skis.

There is thus a need for a new type of ski which makes turning easier, without reducing stability.

According to a first aspect of the present invention there is provided a pair of skis for simultaneous use by a skier, each ski comprising:—

a front ski section and a rear ski section, each having a central longitudinal axis and a skiing surface;

boot binding fixing locations on the front ski section; and

connecting means (connector) for connecting the rear ski section to the front ski section rearward of said boot binding fixing locations such that, in a neutral configuration, the central longitudinal axes of the front and rear ski sections are substantially in linear alignment, and the skiing surfaces of the front and rear ski sections are substantially in planar alignment, and such that the rear ski section is capable of swinging sideways relative to the front ski section whereby the central longitudinal axes of the front and rear ski sections move out of linear alignment, and the rear ski section is capable of moving up and down relative to the front ski section whereby the skiing surfaces of the front and rear ski sections move out of planar alignment.

Thus, the rear ski section is able to rotate rightward and leftward relative to the front ski section, ie, to rotate within the plane of the ski. At the same time, the rear ski section is able to slide, swing or tilt upward and downward in relation to the front ski section.

The ability of the rear ski section to swing sideways relative to the front ski section allows the skier to turn more easily than with conventional skis, as the resistance to turning is reduced due to the reduced length of the front ski section. However, since the total surface area in contact with the snow is approximately the same as that of a conventional ski, the stability of the ski is not reduced.

The ability of the rear ski section to move up and down relative to the front ski section prevents the rear ski section becoming caught or jammed during turns when it is on higher ground than the front ski section by allowing the rear ski section to lift up. This ensures that the rear ski section is free to swing sideways during turns. The ability of the rear ski section to move up and down also allows the ski to slide smoothly over irregularities in the surface of the snow.

Preferably, the front and rear ski sections are connected by said connecting means such that the rear ski section is not capable of substantial rotation about its central longitudinal axis.

The connecting means preferably comprises a first joint for allowing said sideways swing of the rear ski section relative to the front ski section, and a second joint for allowing said up and down movement of the rear ski section relative to the front ski section.

The first joint is preferably a pivotal connection. The second joint is preferably a pivotal connection, for example a hinge. The hinge may comprise a relatively flexible section across the width of the ski. For example, the hinge may comprise a section of elastomeric material. However, the hinge may comprise any alternative joint which connects two parts such that one can swing relative to the other.

The second joint is preferably located rearward of the first joint. Alternatively, the second joint may be located forward of the second joint, or at substantially the same longitudinal position as the second joint.

The connecting means may comprise a single joint for allowing both said sideways swing and said up and down movement of the rear ski section relative to the front ski section. The single joint may comprise a pivotal connection.

The rear ski section is preferably free to swing sideways relative to the front ski section within an angular range substantially centred on the central longitudinal axis of the front ski section. Said angular range is preferably at least 5 degrees or at least 10 degrees and no more than 90 degrees. More preferably, said angular range is at least 30 degrees and no more than 70 degrees. More preferably still, said angular range is substantially 60 degrees.

For example, in the case of a 60 degree angular range, the rear ski section can rotate to a maximum angle of approximately 30 degrees both to the right and to the left of the longitudinal axis of the front ski section.

The angular range is preferably limited by a swing limiter, which may comprise one or more abutment surfaces provided on one of the front and rear ski sections, for abutting (a) corresponding surface(s) provided on the other of said front and rear ski sections at required angular limits.

In a preferred embodiment, each ski may comprise linear alignment locking means (linear alignment lock) for locking the ski in a configuration in which the central longitudinal axes of the front and rear ski sections are substantially in linear alignment. In this way, a user may disable the sideways swing of the rear ski section if desired.

In a preferred embodiment, each ski comprises linear alignment biassing means (linear alignment biassing device), for exerting a return force which urges the rear ski section towards a central position in which the central longitudinal axes of the front and rear ski sections are substantially in linear alignment.

This ensures that the rear ski section returns to the central position once a turn is complete.

The linear alignment biassing means preferably comprises at least one biassing spring, preferably two biassing springs. The or each biassing spring is preferably a tension spring.

The linear alignment biassing means preferably further comprises adjustment means (adjustor) for adjusting the linear alignment biassing means to vary the force exerted by the linear alignment biassing means.

Thus, the strength of the force exerted by the linear alignment biassing means can be varied to suit the strength, weight or experience of the skier.

In the case where the linear alignment biassing means comprises one or more biassing springs, the adjustment means preferably comprises means for increasing the force exerted by said springs. For example, by extending the biassing spring(s) to increase the tension therein in the case of tension spring(s).

The adjustment means preferably comprises a ratchet mechanism, for releasably extending the biassing spring(s) to adjust the tension therein, and thereby adjust the return force exerted by said spring(s) on the rear ski section.

The adjustment means preferably comprises a ratchet mechanism, for releasably compressing the biassing spring(s) to adjust the compression therein, and thereby adjust the return force exerted by said spring(s) on the rear ski section.

The rear ski section is preferably movable up and down relative to front ski section within a limited angular range. The angular range preferably spans at least 5 degrees, more preferably at least 10 degrees. The angular range preferably spans no more than 45 degrees, more preferably no more than 30 degrees, and optionally no more than 20 degrees.

The angular range may be limited by a downward movement limiter which prevents movement of the rear ski section substantially below the skiing surface of the front ski section.

The angular range may be limited at one end by an upward movement limiter which prevents movement of the rear ski section beyond a predetermined angular limit with respect to the skiing surface of the front ski section.

The or each movement limiter may comprise an abutment surface provided on one of the front and rear ski sections, for abutting a corresponding surfaces provided on the other of said sections at a required angular limit.

In an embodiment, the ski may comprise a planar alignment biassing means (planar alignment biassing device) for exerting a force which urges the rear ski section towards a position in which the skiing surfaces of the front and rear ski sections are substantially in planar alignment.

The planar alignment biassing means may comprise at least one spring, preferably a compression spring.

The planar alignment biassing means helps the rear ski section maintain contact with the ground surface during turns. However, in some embodiments, the weight of the rear portion ski section may be sufficient to maintain contact with the ground surface during turns.

In a preferred embodiment, each ski may comprise planar alignment locking means (planar alignment lock) for locking the ski in a configuration in which the skiing surfaces of the front and rear ski sections are substantially in planar alignment. In this way, a user may disable the up/down movement of the rear ski section if desired.

The length of the rear ski section is preferably between one third and one fifth of the overall length of the ski. More preferably substantially one quarter of the overall length of the ski.

The side edges of the front ski section preferably curve inwardly, such that the front ski section is broader towards the front of the ski than at the mid-section of the ski. Similarly, the side edges of the rear ski section are preferably curved or angled with respect to the central longitudinal axis thereof, such that the rear ski section is broader towards the rear of the ski than at the mid-section of the ski. The ski may have rounded front and/or rear tips.

According to a second aspect of the present invention there is provided a pair of skis for simultaneous use by a skier, each ski comprising:—

a front ski section and a rear ski section, each having a central longitudinal axis and a skiing surface;

boot binding fixing locations on the front ski section;

connecting means for connecting the rear ski section to the front ski section rearward of said boot binding fixing locations such that, in a neutral configuration, the central longitudinal axes of the front and rear ski section are substantially in linear alignment, and such that the rear ski section is capable of swinging sideways relative to the front ski section whereby the central longitudinal axes of the front and rear ski sections move out of linear alignment;

biassing means for exerting a force which urges the rear ski section towards a position in which the central longitudinal axes of the front and rear ski sections are substantially in linear alignment; and

adjustment means for adjusting the force exerted by said biassing means.

The connecting means preferably connects the rear ski section to the front ski section such that, in said neutral configuration, the skiing surfaces of the front and rear ski sections are substantially in planar alignment. Further, rear ski section is preferably capable of moving up and down relative to the front ski section whereby the skiing surfaces of the front and rear ski sections move out of planar alignment.

Other preferred or optional features are as defined in relation to the first aspect of the invention.

Embodiments of the present invention will now be described with reference to the accompanying drawings in which:—

FIG. 1 illustrates a pair of skis which embody the present invention;

FIG. 2 is a side view of the rear end of one of the skis shown in FIG. 1;

FIG. 3 is an enlarged view of the region where the front and rear ski sections meet, with the pivotal coupling mechanism removed for clarity;

FIGS. 4 a and 4 b show the upper and lower plate members which form part of the pivotal coupling mechanism of each ski;

FIG. 5 is an enlarged side view of the pivotal coupling mechanism between the front and rear ski sections;

FIG. 6 is another enlarged side view of the pivotal coupling mechanism between the front and rear ski sections;

FIG. 7 is a view of the pivotal coupling mechanism from the under side of the ski;

FIG. 8 illustrates the skis shown in FIG. 1, with the rear ski sections at maximum displacement during a left turn;

FIG. 9 illustrates the skis shown in FIG. 1, with the rear ski sections at maximum displacement during a right turn;

FIG. 10 illustrates one ski from a pair of skis in accordance with a second embodiment of the invention;

FIG. 11 is another view of the ski shown in FIG. 10;

FIG. 12 is another view of the ski shown in FIG. 10;

FIG. 13 is an enlarged view of part of the rear ski section of one ski from a pair of skis in accordance with a third embodiment of the invention;

FIG. 14 illustrates one ski from a pair of skis in accordance with a fourth embodiment of the invention;

FIG. 15 is an enlarged view of the pivotal coupling mechanism of the ski shown in FIG. 14;

FIG. 16 illustrates the rotational movement of the rear ski section of the ski shown in FIG. 14;

FIG. 17 is an enlarged view of the pivotal coupling mechanism of the ski shown in FIG. 14;

FIG. 18 illustrates vertical displacement of the rear ski section of the ski shown in FIG. 14;

FIG. 19 illustrates the action of the planar alignment locking mechanism of the ski shown in FIG. 14;

FIG. 20 illustrates part of the internal configuration of the pivotal coupling mechanism of the ski shown in FIG. 10; and

FIG. 21 illustrates tension adjustment of the pivotal coupling mechanism shown in FIGS. 14-20.

Features common to different embodiments and different figures are given the same reference numerals throughout the figures.

The terms front/forward, rear/rearward, right/rightward, and left/leftward as used herein are defined with reference to the skis, as perceived by a skier using the skis. The terms up/upward and down/downward as used herein are defined with reference to the skis when oriented substantially horizontally with their skiing surfaces facing down.

FIG. 1 shows a pair of skis which embodies the present invention. Each ski 10 comprises a front ski section 12, which resembles the front and mid-portions of a conventional parabolic ski, and a tail section (rear ski section) 14, which resembles the tail portion of such a ski. However, unlike a conventional ski, the front and rear ski sections are not integrally formed, but are connected via a pivotal coupling mechanism 16 rearward of a boot receiving region 18 of the ski.

The front ski section 12 is approximately three times the length of the rear ski section 14, such that, when the longitudinal axes A, B of both sections are aligned, the front ski section represents approximately three quarters of the overall length of the ski 10.

The long, side edges 13 of the front ski section 12 curve inwardly, such that the ski 10 is broader towards the front end of the ski than at its mid-section. The long side edges 15 of the rear ski section 14 follow the same curve such that the rear ski section is broader towards the rear end of the ski, than the mid-section of the ski.

The front ski section 12 curves upwards at its front end and terminates in a rounded end which forms the front tip of the ski. The opposite (rear) end of the front ski section 12 terminates in a concave edge 32, as shown in FIG. 3.

The rear ski section 14 curves upwards at its rear end, but to a lesser extent than the front tip of the ski, and terminates in a rounded end. The opposite (front) end of the rear ski section 14 terminates with a convex edge 34 as shown in FIG. 3.

Front and rear boot binding members 18 f, 18 b, are mounted to boot binding fixing locations (not shown) on the upper surface of the front ski section 12. The rear boot binding member 18 b is mounted approximately 5 cm from the rear end of the front ski section 12. The front boot binding member 18 f is mounted a suitable distance in front of the rear boot binding member, to form a boot binding 18 for receiving a ski boot (not shown), as is well known in the art.

As shown in FIG. 2, upper and lower plates 22, 24 are provided for coupling the rear of the front ski section 12 to the front of the rear ski section 14.

The upper and lower plates are respectively mounted to the upper and lower surfaces of the front ski section 12 by means of three bolts 26.

The upper plate 22 is shown in FIG. 4 a and the lower plate 24 is shown in FIG. 4 b. Both the upper and lower plates have an elongate rectangular form, and a central longitudinal axis C, D. The width of each plate section is substantially equal to the mid-section width of the ski.

Three bolt holes 36 are formed through the thickness of the front ski section 12, in the region behind the rear boot binding member, as shown in FIG. 3. Three bolt holes 42, 44 are formed in corresponding locations through the thickness of both the upper and lower plates 22, 24.

When mounted to the front ski section 12, the longitudinal axes, C, D of the upper and lower plates 22, 24, are aligned with the central longitudinal axis A of the front ski section.

The three bolts 26, which connect the upper and lower plates 22, 24 to the front section of the ski 10, are inserted from the under side of the ski, such that the bolt heads engage the lower plate 22. The bolt heads are countersunk to form a smooth surface with the lower plate, as shown in FIG. 7. The lower plate has a thickness of substantially 1.5 mm and is thinned along its front edge to form a smooth transition between the plate, and the lower surface of the front ski section.

As shown in more detail in FIGS. 5 and 6, the upper and lower plates 22, 24 are secured in position by means of washers 52 and nuts 54 threaded on to the bolts 26 from the upper side of the ski 10.

The rear ski section 14 is attached to the upper and lower plates 22, 24, by means of a fourth bolt 28. A bolt hole 38 is formed through the thickness of the rear ski section, at a position near the front of the section, on its central longitudinal axis B. Corresponding bolt holes 46, 48 are formed along the central longitudinal axes C, D of the upper and lower plates 22, 24. These bolt holes are positioned in relation to the bolt hole 38 in the rear ski section, such that when the fourth bolt 28 is inserted through the three bolt holes, there is a clearance 31 of substantially 1 cm between the curved edges 32, 34, of the front and rear ski sections.

The fourth bolt 28 is inserted through the respective bolt holes from the under side of the ski, and the bolt head is countersunk to form a smooth surface with the lower plate 22, as shown in FIG. 7. As shown in FIG. 5, a washer 56 is inserted between the lower plate 24 and the rear ski section 14 to separate the rear ski section from the lower plate. The bolt is retained in position by means of washers 57 and an adjustable nut 58.

The bolt hole 38 is lined with a cylindrical metal insert (not shown) to prevent wear of the rear ski section as it pivots about the shaft of the fourth bolt 28.

The diameter of the bolt hole 38 in the rear ski section 14 is slightly larger than the diameter of the fourth bolt 28. This, in combination with the respectively convex and concave surfaces 32, 34 of the rear end of the front ski section 12 and the front end of the rear ski section 14, and the clearance 31 therebetween, allow the rear ski section to rotate about the fourth bolt, and thus to rotate relative to the front ski section.

The angular range of rotation is limited by right and left abutment surfaces 33 r, 331. Abutment surfaces 33 r, 331 are located on the convex surface 34 of the front end of the rear ski section 14, close to the respective right and left side edges of the section.

The left side abutment surface 331 is configured to abut the concave surface 32 of the front ski section 12 when the rear ski section 14 is oriented at approximately 30 degrees to the left of the longitudinal axis A of the front ski section. This prevents rotation to the left beyond approximately 30 degrees.

Similarly, the right side abutment surface 33 r is configured to abut the concave surface 32 of the front ski section 12 when the rear ski section 14 is oriented at approximately 30 degrees to the right of the longitudinal axis A of the front ski section. This prevents rotation to the right beyond approximately 30 degrees.

Between these orientations, both abutments 331, 33 r clear the concave surface 32 of the front ski section 12, such that the rear ski section 14 is free to rotate relative to the front ski section through an angular range of approximately 60 degrees.

In the present embodiment, abutments 331, 33 r comprise adjustable screws which are screwed into the concave surface 34 of the rear ski section 14. The skis may be screwed further into, or out of the rear ski section, to adjust the range of angular movement of the rear ski section.

The upper plate 22 has a thickness of substantially 5 mm, and is angled along its length to extend both upwardly and towards the rear end of the ski from its point of attachment to the front ski section 12, as shown in FIGS. 2, 5 and 6. As shown in more detail in FIG. 5, this means that the space between the upper and lower plates 22, 24, is greater than the thickness of the rear ski section 14, which is substantially equal to the thickness of the front ski section 12. Accordingly, the rear ski section is free to move up and down within a limited range relative to the front ski section. For example, the rear ski section may slide vertically on the fourth bolt 28, or may tilt upwards or downwards with respect to the fourth bolt.

The angle of the rear end of the upper plate 22 with respect to the plane of the ski, is approximately 20 degrees. In other embodiments, this angle is preferably between 0 and 30 degrees.

The upper plate 22 is resilient, such that its curvature can be adjusted by adjusting the position of the adjustable nut 58 with respect to the fourth bolt 28, to control the range of vertical movement of the rear ski section 14.

In use, a skier inserts their ski boots into the respective boot bindings 18 of a pair of skis 10, and points the front tips of the skis down hill to start skiing. With the skier's weight substantially evenly distributed over the skis, the skis move down hill in a straight line. Under these conditions, the rear ski sections 14 naturally move to or stay in their centre positions in which their longitudinal axes B are aligned with the longitudinal axes A of the front ski sections, as shown in FIG. 1.

To turn left, the skier shifts their weight to roll the front ski sections 12 on to their left side edges. This causes the front ski sections to flex, and turn naturally to the left, whilst the rear ski sections 14 continue to follow the original straight path. As the turn progresses, the rear ski sections reach their maximum angular displacement with respect to the front ski sections. This configuration is illustrated in FIG. 8.

When the turn is completed, the forward momentum of the skis draws the rear ski sections back towards their central position, with their longitudinal axes B in line with the longitudinal axes A of the respective front ski sections, ready to follow a new straight path at the end of the turn.

Similarly, to turn right, the skier shifts their weight to roll the front ski sections 12 on to their right side edges. This causes the front ski sections to flex, and turn naturally to the right, whilst the rear ski sections 14 continue to follow the original straight path. As the turn progresses, the rear ski sections reach their maximum angular displacement with respect to the front ski sections. This configuration is illustrated in FIG. 9.

Again, when the turn is completed, the forward momentum of the skis draws the rear ski section back towards their central position, with their longitudinal axes B in line with the longitudinal axes A of the respective front ski sections, ready to follow a new straight path at the end of the turn.

Thus, when the skier initiates a turn to the left, the skis temporarily transform to act as left turning skis. Similarly, when the skier initiates a turn to the right, the skis temporarily transform to act as right turning skis. The effect of this is to deepen or accentuate the curvature along the inside edge of each ski (the left side edge when turning left, and the right side edge when turning right). This tightens the turning radius of the ski, and makes it easier for the skier to turn. In practice, once the skier has made the initial effort to initiate the turn, the skis will automatically continue to carve an arc through the snow to complete the turn, with little or no additional effort required of the skier.

FIGS. 10 to 12 illustrate a second embodiment of the present invention. The second embodiment comprises the features of the first embodiment, which are labelled with the same reference numerals in FIGS. 10 to 12. In addition to these features, the second embodiment comprises a light weight tension spring 90, which is attached at one end to an attachment point 92 near the rear end of the upper plate 22 located on the central longitudinal axis D, and at the other end to an attachment point 94 near the rear end of the rear ski section 14, located on the central longitudinal axis B.

In use, as the skier turns to the right or left, the front end section 12 of each ski 10 turns relative to the respective rear ski section 14, thereby increasing the distance between the attachment points 92, 94, and increasing the tension in the spring 90. The increased tension in the spring acts as a restorative force which tends to draw the rear ski section back towards its central position, with its central longitudinal axis B aligned with the central longitudinal axis A of the respective front ski section.

Although the tension in the spring 90 has an upward component, this is counteracted by the weight of the rear ski section 14, such that the underside of the rear ski section remains in contact with the snow.

FIG. 13 illustrates a third embodiment of the invention. The third embodiment comprises the features of the first and second embodiments which are labelled with the same reference numerals in FIG. 13. In addition, a compression spring 130 is provided between the upper plate 22 and the rear ski section 14. The compression spring biasses the rear ski section in a downward direction.

This assists in maintaining contact between the underside of the rear ski section 14 and the snow. At the same time, however, the rear ski section is free to lift or tilt upwards against the action of the spring, to enable the rear ski section to pivot with respect to the front ski section 12 during turning.

FIG. 14 illustrates a fourth embodiment of the invention. The ski illustrated in FIG. 14 comprises a front ski section 12 and a rear ski section 14, which are similar in form to the corresponding ski sections of the first to third embodiments. The front and rear ski sections are connected by a pivotal coupling mechanism 16′, which is located rearward of boot binding fixing locations 18′ of the ski.

As with the previous embodiments, the rear end of the front ski section 12 terminates in a concave edge, whilst the front end of the rear ski section 14 terminates with a correspondingly formed convex edge. The convex end of the rear ski section is received by the concave end of the front ski section, with a small clearance therebetween. These ends are respectively formed to allow rotation of the rear ski section relative to the front ski section about a pivot point P, located substantially on the central longitudinal axis of the rear ski section, close to its front end.

As shown in more detail in FIGS. 15 and 17, the pivotal coupling mechanism 16′ comprises a housing 133, which is fixedly mounted at the rear end of the front ski section 12, and projects over a front portion of the rear ski section 14. A pivot shaft (not shown) is fixedly mounted to the rear ski section at the pivot point P, and extends upwardly therefrom, perpendicular to its longitudinal axis, and engages with the housing 133. The engagement between the pivot shaft and the housing does not allow for substantial movement of the rear ski section relative to the front rear ski section in the axial direction of the shaft, but allows for relative rotational movement. Thus, the rear ski section is free to swing or rotate relative to the front ski section.

The angular range of rotation may be limited by abutment surfaces (not shown), provided on one of the front ski section and the rear ski section, which abut against correspondingly formed surfaces on the other of said sections, when the rear ski section has swung out to a particular angular displacement, to prevent rotation beyond this limit.

The internal structure of the pivotal coupling mechanism 16′ is shown in more detail in FIG. 21. The mechanism comprises a ring member 132 which is substantially centred on the pivot point P, and can rotate relative to the housing.

The ring member 132 houses a right biassing spring 140 and a left biassing spring 142, which respectively extend around right and left sides of the ring member, following an annular path defined by the ring member. Both biassing springs are tensions springs in this embodiment, although in other embodiments they may be compression springs. One end of each spring is attached to the ring member at points W and X respectively. Point W is substantially diametrically opposite to point X. The right and left springs extend in the same direction along around the ring member, and are respectively attached at their opposite ends to blocks 143, 144, which are fixed in relation to the housing 133, at diametrically opposite points Y and Z. Blocks 143, 144 are free to move along the annular path of the ring member, within a limited angular range. Thus, the length of both springs, and thus the tension therein, can be adjusted through rotation of the ring member relative to the housing.

The frontmost ends of each spring 140, 142 are coupled, by means not shown, to the front ski section. The rearmost ends of each spring are coupled, by means not shown, to the rear ski section of the ski.

The ring member 132 comprises a projection 145 which projects outwardly though an opening in the housing 133, such that it can be grasped by a user to rotate the ring member relative to the housing, as illustrated in FIG. 20.

The ring member 132 comprises a series of ratchet teeth 146 which engage with a pawl member 147 located in the housing 133. The ratchet mechanism allows the ring member to be rotated in a direction which extends the right and left springs, to increase the tension therein, but to prevent substantially any movement in the opposite direction. The pawl member is associated with a lever 134 which projects through an opening in the housing 133, such that the pawl member can be disengaged with the ratchet teeth through operation of the lever, whereupon the ring member will automatically return to a neutral position in relation to the housing.

The pivotal coupling mechanism 16′ comprises a locking mechanism, which comprises a button 135 shown (see FIGS. 15 and 17). Button 135 can be depressed by a user when the central longitudinal axes of the front and rear ski sections are aligned, to releasably engage both sections of the ski, and prevent the rear ski section swinging to the right or left relative to the front ski section.

As illustrated in FIG. 18, an elastomeric hinge 136 is located rearward of the pivotal coupling mechanism 16′. This allows the rear ski section 14 to lift up rearward of the hinge relative to the front ski section.

The hinge is configured to prevent the rear ski section dropping below a position in which its skiing surface is substantially in planar alignment with the skiing surface of the front ski section 12.

A locking mechanism is associated with the hinge 136. As illustrated in FIG. 19, a locking panel 131 is slidable over the hinge 136, to prevent the rear ski section 14 rearward of the hinge moving up or down relative to the front ski section 12.

In use, the ski of the fourth embodiment operates substantially as described in relation to the first to third embodiments. More specifically, when the rear ski section 14 rotates to the right relative to the front ski section 12, as illustrated in FIG. 16, the left biassing spring 142 will extend. This increases the tension in the left biassing spring, which provides a returning force which urges the rear ski section back towards a central position in which its central longitudinal axis is aligned with that of the front ski section. Similarly, when the rear ski section of the ski rotates to the left relative to the front section of the ski, as illustrated in FIG. 16, the right biassing spring 140 will extend, providing a returning force which urges the rear ski section back towards said central position.

The strength of the returning force can be adjusted to suit the requirements of a particular skier by adjusting the tension in biassing springs 140, 142, as illustrated by FIG. 20. In this respect, a skier or a technician is able to increase the tension in the springs by moving the projection 145 relative to the housing 133. This rotates the ring member 132 relative to the housing 133, and thus extends the biassing springs increasing the tension therein. To release the tension in the springs, they operate the lever 134, to disengage the pawl member with the ratchet teeth, whereupon the mechanism automatically reverts to a position in which the tension in the biassing springs is minimum.

The hinge allows the rear ski section to lift up relative to the front ski section. This prevents the rear ski section becoming caught or jammed during turns when it is on higher ground than the front ski section. This also allows the ski to slide smoothly over irregularities in the surface of the snow.

If the user wishes to use the skis as conventional skis, they can achieve this by depressing lock button 135, to prevent rightward and leftward rotation of the rear ski section relative to the front ski section, and by sliding panel 131 over hinge 136 to prevent the rear ski section rising up relative to the front ski section during turns. Similarly, if they merely wish to disable the up/down movement of the rear ski section relative to the front ski section, they can achieve this by sliding panel 131 over hinge 136. Alternatively, if they merely wish to disable the right/left swing of the rear ski section relative to the front ski section, they can they can achieve this by depressing lock button 135.

It will be understood that the embodiments illustrated above show applications of the invention only for the purposes of illustration. In practice, the invention may be applied to many different configurations, the detailed embodiments being straightforward for those skilled in the art to implement.

In particular, it will be appreciated that the plates and bolts which form the pivotal coupling mechanism between the front and rear ski sections in the first to third embodiments are described merely for the purposes of illustration, and may be replaced by alternative arrangements, as would be straightforward for a person skilled in the art to implement. For example, the upper and lower plate members may be fixed to the rear ski section, and pivotally mounted to the front ski section. In another example, the rear section of the ski may be provided with an integrally formed tongue, which projects from the front of the rear section, to be locatable within an opening formed in the rear of the front ski section, and retained therein by means of pin or other pivotal engagement means. Alternatively, a tongue could be provided on the front ski section, and a corresponding opening in the rear ski section.

Moreover, the pivotal coupling mechanism, whilst being located rearward of a boot receiving region of the ski, need not be located rearward of the rear boot binding member. For example, it may be located beneath the rear boot binding, or be integrated within the rear boot binding.

It will also be appreciated that the springs of the second to fourth embodiments described above may be replaced by any other suitable biassing means. 

1-45. (canceled)
 48. A pair of skis for simultaneous use by a skier, each ski comprising: a front ski section and a rear ski section, each having a central longitudinal axis and a skiing surface; boot binding fixing locations on the front ski section; and connecting means for connecting the rear ski section to the front ski section rearward of said boot binding fixing locations such that, in a neutral configuration, the central longitudinal axes of the front and rear ski sections are substantially in linear alignment, and the skiing surfaces of the front and rear ski sections are substantially in planar alignment, and such that the rear ski section is capable of swinging sideways relative to the front ski section whereby the central longitudinal axes of the front and rear ski sections move out of linear alignment, and the rear ski section is capable of moving up and down relative to the front ski section whereby the skiing surfaces of the front and rear ski sections move out of planar alignment, wherein the connecting means comprises a first joint for allowing said sideways swing of the rear ski section relative to the front ski section, and a second joint for allowing said up and down movement of the rear ski section relative to the front ski section, and wherein the second joint is located rearward of the first joint.
 49. The pair of skis as claimed in claim 48, wherein the first joint is a pivotal connection and a pivot point of said pivotal connection is located on the rear ski section.
 50. The pair of skis as claimed in claim 48, wherein the front and rear ski sections are connected by said connecting means such that the rear ski section is not capable of substantial rotation about its central longitudinal axis.
 51. The pair of skis as claimed in claim 48, wherein the rear ski section is free to swing sideways relative to the front ski section within an angular range substantially centered on the central longitudinal axis of the front ski section, and said angular range is at least 10 degrees and no more than 90 degrees.
 52. The pair of skis as claimed in claim 48, wherein each ski comprises linear alignment biassing means, for exerting a return force which urges the rear ski section towards a central position in which the central longitudinal axes of the front and rear ski sections are substantially in linear alignment.
 53. The pair of skis as claimed in claim 52, wherein the linear alignment biassing means further comprises adjustment means for adjusting the linear alignment biassing means to vary the force exerted by the linear alignment biassing means.
 54. The pair of skis as claimed in claim 48, wherein the rear ski section is movable up and down relative to the front ski section within a limited angular range, and said angular range spans at least 5 degrees and no more than 45 degrees.
 55. The pair of skis as claimed in claim 54, wherein the angular range is limited by a downward movement limiter which prevents movement of the rear ski section substantially below the skiing surface of the front ski section, and the angular range is limited at one end by an upward movement limiter which prevents movement of the rear ski section beyond a predetermined angular limit with respect to the skiing surface of the front ski section.
 56. The pair of skis as claimed in claim 48, wherein the ski comprises a planar alignment biassing means for exerting a force which urges the rear ski section towards a position in which the skiing surfaces of the front and rear ski sections are substantially in planar alignment.
 57. The pair of skis as claimed in claim 48, wherein the length of the rear ski section is between one-third and one-fifth of the overall length of the ski.
 58. A pair of skis for simultaneous use by a skier, each ski comprising: a front ski section and a rear ski section, each having a central longitudinal axis and a skiing surface; boot binding fixing locations on the front ski section; connecting means for connecting the rear ski section to the front ski section rearward of said boot binding fixing locations such that, in a neutral configuration, the central longitudinal axes of the front and rear ski section are substantially in linear alignment, and such that the rear ski section is capable of swinging sideways relative to the front ski section whereby the central longitudinal axes of the front and rear ski sections move out of linear alignment; linear alignment biassing means for exerting a force which urges the rear ski section towards a position in which the central longitudinal axes of the front and rear ski sections are substantially in linear alignment; and adjustment means for adjusting the force exerted by said linear alignment biassing means.
 59. The pair of skis as claimed in claim 58, wherein the connecting means connects the rear ski section to the front ski section such that, in said neutral configuration, the skiing surfaces of the front and rear ski sections are substantially in planar alignment; and the rear ski section is capable of moving up and down relative to the front ski section whereby the skiing surfaces of the front and rear ski sections move out of planar alignment.
 60. The pair of skis as claimed in claim 58, wherein the adjustment means comprises means for increasing the force exerted by said biassing spring(s) by extending the biassing spring(s) to increase the tension therein.
 61. The pair of skis as claimed in claim 58, wherein the adjustment means comprises a ratchet mechanism.
 62. The pair of skis as claimed in claim 58, wherein the connecting means comprises a first joint for allowing said sideways swing of the rear ski section relative to the front ski section, and a second joint for allowing said up and down movement of the rear ski section relative to the front ski section, and wherein the second joint is located rearward of the first joint.
 63. The pair of skis as claimed in claim 58, wherein the rear ski section is free to swing sideways relative to the front ski section within an angular range substantially centered on the central longitudinal axis of the front ski section, and said angular range is at least 10 degrees and no more than 90 degrees.
 64. The pair of skis as claimed in claim 58, wherein the rear ski section is movable up and down relative to the front ski section within a limited angular range, and the angular range spans at least 5 degrees and no more than 45 degrees.
 65. The pair of skis as claimed in claim 64, wherein the angular range is limited by a downward movement limiter which prevents movement of the rear ski section substantially below the skiing surface of the front ski section, and wherein the angular range is limited at one end by an upward movement limiter which prevents movement of the rear ski section beyond a predetermined angular limit with respect to the skiing surface of the front ski section.
 66. The pair of skis as claimed in claim 58, wherein the ski comprises a planar alignment biassing means for exerting a force which urges the rear ski section towards a position in which the skiing surfaces of the front and rear ski sections are substantially in planar alignment.
 67. The pair of skis as claimed in claim 58, wherein the length of the rear ski section is between one-third and one-fifth of the overall length of the ski. 